More info has surfaced around the motive in the Hudson family murders

INSIDE STORY: How a Gift Allegedly Triggered Jennifer Hudson Murders
It all started from Julia Hudson's birthday. On Oct. 23 Julia celebrated with cake and a small party at home.

The next morning, police say, Julia's estranged husband William Balfour showed up and spotted a gift he believed came from another man.

Police believe that jealousy is the motive that led Balfour, 27, to return to the house after Julia had left for work and shoot her mother Darnell Donerson, 57, Jennifer's brother Jason, 29, then take Julia's son, 7-year-old Julian King, and later kill him as well, prosecutors allege.

The timing of Julian's death is still in question – his body was found three days later in the back seat of Jason's missing SUV, parked on a west side street several miles away – but police believe Julian was shot in the vehicle the same day as the first two murders.

Forensics tests later matched a .45 caliber handgun found in an alley near the parked Suburban with shell casings found at the house. And prosecutors said the gun belonging to Jason Hudson had been stolen by Balfour last summer and seen by Balfour's girlfriend, to whom they say he admitted his role in Donerson's and Jason Hudson's deaths.